int diagonalSum(int** mat, int matSize, int* matColSize) {
	int i = 0;
	int sum = 0;	
	for (i = 0; i < matSize; i++) {
		int j = 0;
		for (j = 0; j < matSize; j++) {
			if (i == j || i + j == matSize - 1) {
				sum += mat[i][j];
			}
		}
	}
	return sum;
}